1. Field
The following description relates to an image fusion apparatus and method for composing multi-exposure images obtained from an image sensor, and more particularly, to a multi-exposure image fusion apparatus and method for producing a sharp high-resolution high dynamic range (HDR) image to more fully represent detail in under and over-exposed regions of an image without contrast degradation.
2. Description of the Related Art
Examples of a conventional high dynamic range (HDR) image generation include an image obtaining method using an HDR image sensor and a multi-exposure image composition method. The image obtaining method uses an HDR image sensor to obtain an HDR image directly from an image sensor. The image obtaining method does not perform image synthesis.
The multi-exposure image compositing method includes global/local tone mapping methods, each of which captures a plurality of images with different exposures and generates HDR data. The method includes compressing the HDR data by tone mapping in accordance with a low dynamic range (LDR) to generate an output image.
The global tone mapping method may retain the global contrast, and is simple to calculate. However, in the global tone mapping method, the local contrast is degraded and an unclear image is obtained. The local tone mapping can retain the local contrast, but an inversion phenomenon and halo artifacts may occur, and a large amount of calculations are required.
In addition, the above methods are not sufficient to provide an HDR image corresponding to the recent trend of high quality images and contrast characteristics of human vision.
For example, the multi-exposure image composing method may produce an image with deteriorated quality due to contrast degradation that results from dynamic range compression. The multi-exposure image composing method may cause the occurrence of an inversion phenomenon and halo artifacts. Therefore, a new HDR image generating method that does not reduce global or local contrast is needed.